Power-operated, predetermined torque release hand tool



March 24, 1953 w. H. PECK 2,632,485

POWER-OPERATED, PREDETERMINED TORQUE RELEASE. HAND TOOL INVEN TOR. Mu/AMH PfZk piston shownin Fig. 2;

Patented Mar. 24, 1953 UNITED- STATES.

TENT OFFICE O ikPOWER OPE-RATED, PREDETERMINED TORQUE RELEASE HAND TOOL"William H. Peck, Royal Oak, Mich.

Application January 13, 1950, Serial No. 138,348

f hi inventionrelate to 11001 an m p ticularly toga. power driven toolfor turning nuts, bolts, screwsand the like, commonly referred to as. atorque wrench y Heretofore torque wrenches have been made wherein theturning force is indicated to the operator or the tool is permitted toturn relativeto the work after apredetermined torque hasbeen, applied.to the work, such as in the use of slippingclutches and the like.

The present invention, while pertaining generally to such a toolrelatestoimproved features of operation and construction designed toaccom- Azfurtherobject.ofthe invention is to provide coolingmeans forthe working parts of the device to remove the heatgenerated-by theconversion of torque motion into reciprocating motion.

A still further object ofthe invention is to provide a clutch betweenthework and the torque conversion mechanism which is operable bypressure engagement of the tool with the work.

1 Othenobjects and'advantages of the invention will more fully appearfrom the following description taken in connection with the accompanyingdrawings in which;

Fig. 1 is a side elevational view of a tool showing my improved'deviceapplied thereto;

Fig. 2 is 'an-enlargedsectional view taken on line 2 2 of Fig. 1;

Fig. 3 isa sectionalview-taken online 3- -3 of Fig.2;

' Fig.4'isa sectional view taken on line 4-4 of Fig-2; V e w Fig.5 isa'sectionalfview taken on line 5-5 Fig. 6 is a perspective view of thereciprocating Fig. 7 is a view correspo nding to Fig. 2 but showing amodified'form oi? the invention;

Fig. 8- is a view corresponding to Fig. 2 but {showing afurthermodiflcation of the invention;

10, adapted to slidingly receive the outer end of 6 C a ms. (01. 144- 2)Fig. 10 is a sectional view taken on line Ill-40 of Fig. 8; I f I Fig.11 is a sectional view taken on line H--ll ofFig.7; M

Fig. 12 is a developed view showing the groove in the peripherialsurface ofthe reciprocating piston shown in Figs. 2 and 6; and

Fig. 13 is a developed .view showing one of the grooves in theperipherial surface of the reciprocating piston shown in Fig. 8. ll

Referring to the drawings, I have shown'the tool having a body portion20 in which an electric motor is mounted for power driving means to atransmission housing 22. The body,portion 20 is provided with a handle24, a finger control switch 25, and an electrical lead 28. Thetransmission housing 22 is providedwitha threaded end portion 36 and adriving shaft 32 which is rotated through the transmission by the motorin the body 20. y i

My improved mechanism is adapted to be received on the threaded endportion 30 and the operating mechanism has a drivingconnection with theshaft 32. The driven torque conversion mechanism comprises a tubularcasing 34 adapted to be screw threaded on an adapter 35 whichliits thethreaded end portion 30.

A sleeve 38 isrotatably supported in the casing 34 and is journaled in abearing 40. The sleeve 38 has a removable head 42 which forms therewitha piston chamber 44, one end being closed as at 50 and the. opposite endsealed with the head 42 by a packing 52. Screws 53 retain the head 42 onthe sleeve 38., An axially extending shaft 54 is rotatably supportedinthe head 42. A packing. member 56 forms a seal between the shaft 54and the head 42 withone end-of the shaft 54 projecting into the pistonchamber. The opposite end of the shaft 54 ispiloted, as at 58, into thedriving shaft .32. Externally of the head 42 and adjacent the pilot 58the shaft 54 has a rectangular portion 50 which receives a sleeve 62.One -end of the sleeve 62 fits the rectangular portion and a set screw64 secures the sleeve 62 to the shaft 3 2. In addition to the screw 54,the outer face of the shaft 32 is flattened as atfifi to form a drivingconnection from the shaft 32 through the sleeve 62 to the shaft 54. i

A piston 68- having anaxially extending bore the shaft 54,.is slidablymounted in the piston chamber 44 relative tothe sleeve 38 and the shaft.54. To prevent relative rotation of; the piston 68 and the shaft. 54and yet. permit relative axial 3 movement, a plurality of balls I2 arearranged in oppositely disposed grooves I4 and I6 in the adjacent facesof the piston 88 and shaft 54 respectively.

Thepiston chamber 44 is divided into two pressure chambers A and B bythe piston 88. A transverse passage I8 in the piston head and an axiallyextending passage 80, connecting the passage !8, the bore I and groovesI4 and I6, from an intercommunication between the two chambers A and B,so that as the piston is moved axially in the chamber 44 the fluid isconducted from one of the chambers A and B to the other through thepassages I4, 80 and I3. In addition to these passages, there areprovided passages 59 and BI in the shaft 54 to permit a flow of fluidfrom one chamber to the other.

A cam track in the form of a zig zag groove 82, more clearly shown inFigs. 6 and 12, is formed in the outer periphery of the piston 58. Aball 84 or, as shown, radially disposed balls are received in radialapertures 86 in the wall of the sleeve 38. These balls are positioned inthe groove 82 and form a driving connection between the piston 88 andthe sleeve 38. The balls 84 are held radially inwardly by plugs 88 whichin turn are held in position by a press fit ring 90 on the outerperiphery of the sleeve 38. By relative rotation of the piston 88 andthe sleeve 88 the balls 84, in the cam track 82, cause the piston 58 toreciprocate axially relative to the sleeve 33, thus alternating thepressures in the chambers A and B with the fluid flowing from one to theother through the passages 8|,"I9, I4, I0, 80 and 78.

An inter-changeable restriction comprising a threaded plug 92, having aprojection 94 substantially the diameter of the passage is and in axialalignment therewith, is threaded in the head of the piston 88. Theprojection 94, depending upon its axial position with respect to theopening of the passage I8, restricts the flow of fluid from one of thechambers A and B to the other. A locking screw 96 hold-s the plug 92 inadjusted position. An opening 98, in axial alignment with the plug 92and screw 98, is provided to permit access to the screw and plug. Aclosure I00 is provided for the opening 98.

At the outer end of the sleeve 38 one member I02 of a jaw clutch issecured by screw M4 to an extension I08 of the sleeve 38. The othermember I08 of the jaw clutch is journaled in a bushing IIO mounted inthe outer end of the casing 34. A pin I I2 having a head I I4, thelatter fitting a counterbore H6 in the jaw clutch member W8, is pilotedinto a bore H8 in the sleeve 38. A coil spring I20 urges the pin H2 andjaw clutch member outwardly for normal dis-engagement of. the jaw clutchmembers. The tool, herein shown as a screw driver I22, has a squareshank and fits a square opening in the clutch member I08 for turningengagement therewith. The tool is retained in position by a springpressed ball I24 fitting a notch in the shank of the tool. A spring Cring I25 resiliently holds the ball in retaining position so that thetool can be spring pressed into or out of position.

A fan I26, mounted for rotation with the sleeve 38 and when rotatingwith the sleeve, causes a circulation of air through openings I28 andI30 for cooling the rotating parts within the casing 34.

When the switch 28 is turned on the motor in the body portion 20 rotatesthe shaft 32 causing rotation of the shaft 54 and piston 68. With therestriction in the flow of fluid from one chamber to the other, A or B,the resistance to axial movement of the piston 68 is great enough tocause the cam track, acting through the balls 84, to rotate the sleeve38. This rotation causes rotation of the one clutch member I02 but doesnot cause rotation of the screw driver I22 because the clutches arenormally disengaged. When the operator applies the tool to a work piecean axial pressure causes the tool I22, clutch member I08 and the pin I2to move axially inwardly against the pressure of the spring I20. Thiscauses engagement of the clutch members I02 and I08 establishing adriving connection from the rotating sleeve 38 to the tool I22. As soonas the torque force has reached a predetermined load, as by the turningresistance of the work, the torque load is increased on the piston 68which, due to the cam track 82, produces an axial pressure on thepiston. This pressure is resisted by the flow of fluid from one chamberto the other, the resistance of which is dependent upon the restrictionfrom the passage I8 to the passage 80. After the resistance of the axialmovement of the piston is overcome by the torque force on the tool I22and sleeve 38, the additional forces are applied to produce areciprocating motion of the piston 88, thereby discontinuing rotarymotion to the sleeve 38 and the torque forces are not increased beyondthe predetermined amount. When the operator releases the axial pressureon the work, as in removing the tool from the work, the spring I20forces the clutch member I08 outwardly, disengaging the clutch membersI02 and I08 so that there is no torque resistance to the sleeve 38whereupon it starts turning with the turning of the shaft 32, shaft 54and piston 88. Due to the restricted flow of fluid through the passageI8, the piston 88 discontinues its reciprocating motion. By thedisengagement of the clutch members I02 and I08, the tool I22 is nolonger rotated and the operator can easily insert the stationary tool inanother work piece for repeated operation.

The restriction to fluid flow is determined by the size or location ofthe projection 94, on the plug 92, relative to the passage I8.Preferably the plug 92 is designed to seat on a shoulder I32 so that theend of the projection 94 is spaced from the open end of the passage I8 apredetermined distance therefrom, depending upon the variable length ofthe projection 94. However, the projection may be made having a variablediameter to be received in the passage I8 for varying the flowtherethrough. A series of plugs having variable size projections aremaintained so that the operator may select the proper plug to give thedesired restriction depending upon the torque required to be applied tothe work.

The form of the invention illustrated in Fig. 7 is substantially thesame as the form shown in Figs. 2 to 6 inclusive, except formodifications hereinafter set forth. The same numerals designatecorresponding parts, even thoughthere is a slight variation in size andshape. The parts have been reduced in size so that the casing 34 isthreaded directly to the end portion 30'0f the transmission housing 22,.thus eliminating the adapter 38, shown in Fig. 2. The fan I28 has beenmounted on the sleeve 82 which rotates at all times during motor drive.By this arrangement there is a circulation of air through the easingduring rotation or idle conditions -of the sleeve 38. Since there ismore heat generated in the working parts during the time that there isrelative rotation of the sleeve 38 and shaft, this .A transverse passagearrangement of the. fan is preferred to the form shown inFig. 2 whereinthe fan is located on the sleeve 38.

' The balls 84, forming a driving connectionbe tween the piston 68 andthe sleeve 38, are re- Rollers I36-form the driving connection betweenthe shaft 54 and the piston 68 and permit relative axial movement of theparts'through the grooves 14. One of the grooves 14 is extendedoutwardly into the head'of the piston forming a passage 86.

I40 is formed in the piston head and. intersects the passage" 86.. A

passage I42. intersects the passage I40 and extends through the end faceof the piston head to the chamber B. The shaft 54 is provided withpassages 19' and GI for conducting a fluid from the chamber A to thechamber B through the passages BI, 16, 80, I46 and I42.

, In this form of the invention the restriction for the flow of fluidthrough the passages comprises a screw I44 having a projection I46,extending axially of 'the piston, and the screw I44 is threaded into theouter end of the piston head with the end of the projection entering anaperture I48 with the end thereof in contact with the closed end of theaperture I48. The projection extends across the passage I46 and thediameter of the projection relative to the diameter of the passage I40determines the amount of fiuid leak through the passage I46. If it isdesired to increase the restriction to flow a screwrhaving a largerdiameter projection is used. A closure screw I56 is provided in the endof the sleeve 38 to close'the chamber B and permit the operator to haveaccess to the screw I44 for replacement purposes.

The sleeve 38 is journaled in the bearing 46 and the jaw clutch membersI62 and I08 are provided as in the form shown in Fig. 2. The tool I22 isurged outwardly by the spring I26. The operation of the clutches I02 andI88 is the same as described in connection with construction shown inFig. 2.

In the form of the invention shown in Figs. 8, 9, and 13, a springresistance mechanism has been substituted for the fluid pressureresistance, the means for varying the torque pressure has been modified,and the jaw clutch members have been omitted.

A casing I52 is screw threaded to an adapter I54 which is threaded tothe transmission housing 22. The driving shaft 32, through connectorI56, drives an axially extending shaft I58. Rotatably mounted on theshaft I58 is a bearing I 66. Threaded on the bearing I60 is a sleeve I62having its outer end journaled in a bearing I64 supported by the casingI52. The tool I22 is held in the end of the sleeve I62 by means similarto that shown in Figs. 2 and 7.

A piston I66 is mounted in the sleeve I62 for reciprocation and isrotatably driven by the shaft I58 through balls I68 in oppositelydisposed grooves I16 and I12 in the piston I66 and shaft I58respectively. A coil spring I14, surrounding the shaft I58, is undercompression between the inner end of the piston I66 and the outer end ofthe bearing I66. This spring urges the piston I66 axially toward theclosed end of sleeve I62.

A pair of cam tracks I16, one shown in developed form in Fig. 13, areprovided in the peripherial surface of the piston I66. Balls I18,

held in a position to form asdriving connection between the piston I66and the sleeve I62, are held in place by screws I80. Itis to,beunderstood that. while. these balls I18 form a driving connectionbetween the piston I66 and sleeve I62 they are rotatable in the path ofthe grooves I16 during relative rotation of the piston I66 and sleeveI62. I

Referring now specifically to one of the tracks, shown in Fig. 13, thetrack is formed in two parts, an ascending portion, I82 and a descendingportion I84. These tracks are arranged on the peripherial surface of thepiston so that the ascending portion I62 produces a force causing thepiston 166 to move in a direction to compress the spring I14andthedescending portion I84 permits the force of'the spring I14 to move thepiston in the opposite direction. When the torque load on the work isless than the force required to overcome the compression of the springI14, the balls I18 do not rotate in the groove but form a drivingconnection between the piston I66 and the sleeve I62. This is 'dependentupon the angular relation of the ascending portion I82 to the axis ofthe piston I66. If it is desired to increase the torque applied to thework the angle is increased, as designated by the dotted lines I82? inFig. 13; that is, the angle more closely-approaches a line parallel tothe axis of the piston.

-'in the same manner as defined in the construction shown in Fig. 2.

From the above it will be apparent that the structure provides a toolwherein predetermined torque power may be applied to the work and whenthat power has been reached greater torque power is dissipated so thatan overload is not applied to the work. The device permits a variationin the torque power applied, thereby making it applicable to varioustypes of work.

While I have illustrated and described preferred and modified forms ofthe device, it will be understood that various changes including thesize, shape and arrangement of parts may be made without departing fromthe spirit of my invention and it is not my intention to limit its scopeother than by the terms of the appended claims.

I claim:

1. A tool for rotating a work piece comprising, a

rotatable shaft, a piston rotatable with said shaft and axially movablerelative to said shaft, a sleeve forming a, chamber for said piston,said piston dividing the chamber into pressure chambers, one at each endof said piston, a fluid passage through said piston forming acommunication between the two end chambers, a restrictive mean in saidpassage, means including a cam and cam follower for providing a slipdrive connection between said sleeve and said piston whereby relativerotation between said sleeve and said piston pro-- duces relative axialmovement there between, and a work piece engaging member driven by saidsleeve.

2. A tool for rotating a work piece comprising, a rotatable shaft, apiston rotatable with said shaft and axially movable relative to saidshaft, a sleeve forming a chamber for said piston, said piston dividingthe chamber into pressure chambers, one

. at each end of said piston, a fluid passage through said pistonforming a, communication between the two end chambers, a replaceablerestrictive means in said passage, means including a cam and camfollower for providing a slip drive connection between said sleeve andsaid piston whereby relative rotation between said sleeve and saidpiston produces relative axial movement there between, and a work pieceengaging member driven by said sleeve.

3. A tool for rotating a work piece comprising, a rotatable shaft, apiston rotatable with said shaft and axially movable relative to saidshaft, a sleeve forming a chamber for said piston, said piston dividingthe chamber into pressure chambers, one at each end of said piston, afluid passage through said piston forming a communication between thetwo end chambers, a replaceable restrictive means in said passage, meansincluding a cam and cam follower for providing a slip drive connectionbetween said sleeve and said piston whereby relative rotation betweensaid sleeve and said piston produces relative axial movement therebetween, a work piece engagin member driven by said sleeve, and a jawclutch element between said sleeve and said work piece engaging member.

4. A tool for rotating a work piece comprising, a rotatable drivingmember, a rotatable driven member, means including a cam and camfollower forming a driving connection between said members up to apredetermined torque resistance, and producing relative reciprocationand relative rotation of said members beyond the predetermined torqueresistance, and a fluid resistance pressure means for preventingrelative reciprocation of said members.

5. A tool for rotating a work piece comprising, a rotatable drivingmember, a rotatable sleeve forming a chamber around said rotatabledriving member, a reciprocatory member dividing the chamber intopressure chambers, one at the opposite ends of said reciprocatorymember, a driving connection between said driving member and saidreciprocatory member, means for producing a fluid pressure resistance tothe movement of said reciprocatory member, and a slip drive connectionbetween said sleeve and said reciprocatory member whereby resistance tosaid reciprocatory member causes driving engagement between said sleeveand said piston and when the resistance to rotation of said sleeveovercomes the resistance to the reciprocatory member there is relativerotation between said sleeve and said reciprocatory member.

6. A tool for rotating a work piece comprising, an outer rotatablemember, an inner rotatable member, an intermediate rotatable member,said intermediate member being axially movable relative to said innerand outer members, a positive driving connection between said innermember and said intermediate member, a slip drive connection betweensaid outer member and said intermediate member, and fluid pressureresistance means between said intermediate member and said outer member,said intermediate member and said outer member being rotatable in unisonunder a predetermined fluid pressure resistance and being relativelyrotatable above the predetermined pressure resistance.

WILLIAM H. PE'CK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,082,771 Russell Dec. 30, 19131,525,545 James Feb. 10, 1925 1,855,456 Miller Apr. 26, 1932 1,954,620Connell Apr, 10, 1934 2,127,855 Baumg'ratz et al. Aug. 23, 19382,415,552 Broecker Feb. 11, 1947 2,482,995 Willis Sept. 27, 1949

